Semiconductor memory devices, including flash memory, typically utilize memory cells to store data as an electrical value, such as an electrical charge or voltage. A flash memory cell, for example, includes a single transistor with a floating gate that is used to store a charge representative of a data value. Flash memory is a non-volatile data storage device that can be electrically erased and reprogrammed. More generally, non-volatile memory (e.g., flash memory, as well as other types of non-volatile memory implemented using any of a variety of technologies) retains stored information even when not powered, as opposed to volatile memory, which requires power to maintain the stored information.
Writing data to some types of non-volatile memory, including flash memory requires erasing one or more portions of the memory before writing the data to those portions of the memory. As memory (e.g., flash memory cells) goes through repeated cycles of writes and erasures, it gets worn by the application of repeated, high voltage erase operations. Therefore, it would be desirable to rank portions of a flash memory device based on an erase health metric (i.e., one or more metrics determined from memory erase operations).